I bought this after seeing rave reviews on the Net, but frankly I found it a disappointment, even allowing for the fact that it is a Seventies BBC production. Even when compared with other BBC video-taped productions of the time, such as Doctor Who and Survivors, this is terribly slow and unconvincing. The actors are obviously doing their best with the lines they have been given, but honestly their faces display the boredom and dissatisfaction that I experienced when watching this ! I think the problem is with the terribly disjointed scripts. As the DVD booklet relates, this series was conceived and rushed into production with the kind of speed that didn't allow for enough thought to be put into what would nowadays be described as a story "arc". Someone seems to have made the conscious decision that each episode would end, not with a spectacularly frightening event (of which there are many in this series) but with a dull, inconclusive talky scene that makes a half-hearted attempt to persuade us to tune in next week. I felt sorry for actors who were required, week after week, to be demon-possessed or something, yet who had to turn up for the next scene apparently completely unaffected by their experiences ! And could no-one think of a way to end the whole saga? It just peters out ...